Removal Of Different Types Research Articles

Synthesis of a superhydrophilic coral-like reduced graphene oxide aerogel and its application to pollutant capture in wastewater treatment

Inspired by nature, a zeolitic-imidazolate framework-8@reduced graphene oxide (ZIF-8@rGO) aerogel was developed to remove tetracycline (TC) from water. The ZIF-8 nanoparticles grown on the rGO aerogel act like the many tentacles of a coral to hunt TC, and the rGO aerogel not only acts as a substrate but also acts like the belly of the coral, which can accommodate a large number of pollutants. Benefiting from these advantages, the ZIF-8@rGO aerogel can decontaminate TC, and showed an excellent adsorption capacity of 1776.26 mg g−1. Based on the experimental tests and characterization analysis, we speculated that the adsorption mechanism between TC and ZIF-8@rGO aerogel was mainly related to the hydrogen-bonding interactions, π-π interaction and electrostatic attraction. This discovery could be transformative for the removal of different types of pollutants by means of adjusting the functional groups of the materials and their composite technology.

On the way to raising the technology readiness level of diamond electrolysis

During the last decades, hundreds of scientific papers have focused on the use of anodes consisting of conductive diamond coatings, pointing out their outstanding capacity for the mineralization of organic pollutants contained in wastewater. Most of the works consist of the evaluation of the removal of different types of organics, with concentrations ranging from a few micrograms up to several grams per liter, in different matrices, from synthetic solutions containing large concentrations of sulfate or chloride to real wastewater. However, the technology readiness level has been stagnant in the lab at levels 4–5 and, because of the promising results published, there is a need to raise the readiness levels to values that indicate the full-scale applicability. In this review, two of the main challenges that need to be overcome to reach higher readiness levels are reviewed. The first is the improvement in the formulation of the doped diamond coatings targeting to be tailored for dedicated applications. Its significance is explained in terms of the high influence of these anodic surfaces on the efficiencies of the degradation of complex anthropogenic organics and, overall, on the efficient production of oxidants, that extend the oxidation of pollutants from the nearness of the anode surface to the bulk of the wastewater during electrolysis. The second advantage is the improvement in the design of the electrochemical cell that integrates the diamond anode, trying to take advantage of the outstanding properties of the diamond not only by improving the mass transport rates but also by optimizing the combination of its very efficient oxidation paths with other non-electrochemical oxidation mechanisms. • There is a need to increase technology readiness level (TRL) for electrolysis of wastewater with a diamond anode. • Tailoring of the formulation of diamond and cell design are interesting paths to raise TRL. • Tailoring of diamond coatings influences the in-situ production of oxidants during the electrolysis of wastewater. • Mass transport enhancements and efficient combination with other technologies can be attained with improved cell designs.

Heterogeneous Advanced Oxidation Processes: Current Approaches for Wastewater Treatment

Nowadays, water pollution is one of the most dangerous environmental problems in the world. The presence of the so-called emerging pollutants in the different water bodies, impossible to eliminate through conventional biological and physical treatments used in wastewater treatment plants due to their persistent and recalcitrant nature, means that pollution continues growing throughout the world. The presence of these emerging pollutants involves serious risks to human and animal health for aquatic and terrestrial organisms. Therefore, in recent years, advanced oxidation processes (AOPs) have been postulated as a viable, innovative and efficient technology for the elimination of these types of compounds from water bodies. The oxidation/reduction reactions triggered in most of these processes require a suitable catalyst. The most recent research focuses on the use and development of different types of heterogeneous catalysts, which are capable of overcoming some of the operational limitations of homogeneous processes such as the generation of metallic sludge, difficult separation of treated water and narrow working pH. This review details the current advances in the field of heterogeneous AOPs, Fenton processes and photocatalysts for the removal of different types of emerging pollutants.

Remediation of triazole, anilinopyrimidine, strobilurin and neonicotinoid pesticides in polluted soil using ozonation and solarization

This study aimed to investigate the effectiveness of ozonation and solarization techniques for the removal of different types of pesticides from soil during the summer season. The effect of two experimental parameters (temperature and ozone application mode) on the pesticide degradation was evaluated. The results showed that solarization (S), solarization with surface ozonation (SOS), and solarization with deep ozonation (SOD) enhanced pesticide degradation rates in comparison with the control (untreated soil, C). The triazole, anilinopyrimidine, strobilurin and neonicotinoid pesticides showed similar behaviour under S and SOS conditions. The highest decrease was found in SOD, indicating the significant effect of temperature and ozone application mode on the efficiency of the ozonation treatment. Thus, a higher soil temperature and a longer accumulated time at high temperature in treatments S, SOS and SOD were observed due to solarization process. In addition, the removal efficiency was enhanced with exposure time. Finally, the main 15 transformation products were identified during SOD treatment. The results suggest that solarization combined with ozonation techniques allows decontamination of soil containing pesticide residues.

Feasibility of Adsorption Kinetic Models to Study Carrier-Mediated Transport of Heavy Metal Ions in Emulsion Liquid Membranes.

Emulsion liquid membranes have been successfully used for the removal of different types of organic and inorganic pollutants by means of carrier-mediated transport mechanisms. However, the models that describe the kinetics and transport of such mechanisms are very complex due to the high number of model parameters. Starting from an analysis of the similarity between the elemental mechanisms of carrier-mediated transport in liquid membranes and of transport in adsorption processes, this paper presents an experimental analysis of the possibility of applying kinetic and mechanistic models developed for adsorption to carrier-mediated transport in emulsion liquid membranes. We study the removal of a target species, in this case, Cu(II), by emulsion liquid membranes containing membrane phase solutions of benzoylacetone (carrier agent), Span 80 (emulsifying agent) and kerosene (diluent), and hydrochloric acid as a stripping agent in the product phase. The experimental results fit the pseudo-second-order adsorption kinetic model, showing good relationships between the experimental and model parameters. Although both Cu(II) diffusion through the feed/membrane interface boundary layer and complex Cu-benzoylacetone diffusion through the membrane phase controls Cu(II) transport, it is the former step that mainly controls the transport process.

Effect of Chitosan on the Removal of Different Types of Tannins from Red Wines

(1) Background: most premium red wines are rich in tannins but the effect of chitosan on these macromolecules is unknown. In this work, the effect of a treatment with 0.5 g/L of chitosan on red wines, W, enriched with condensed tannins, CT, ellagitannins, ET, and gallotannins, GT, was evaluated. In addition, to understand if the effect of C was stable during wine evolution, treated wines underwent an oxidative stress simulating an exposure to 18 mg/L of oxygen. (2) Methods: parameters describing the reactivity of phenolic compounds were determined: iron reactive phenolics, BSA reactive tannins, vanillin reactive tannins, and the saliva precipitation index. Individual anthocyanins, total and polymeric pigments and chromatic characteristics were evaluated to determine the influence of each treatment on colour parameters. (3) Results: a decrease in BSA reactive tannins after the addition of C was detected for all wines and the effect persisted after oxidation. W and CT wines previously treated with C and oxidized showed a significant decrease in the reactivity towards salivary proteins. C caused a lower formation of polymeric pigments in all wines. (4) Conclusion: these results suggest a possible use of C to treat wines very rich in condensed tannins and excessively astringent.

Assess the performance of chemical coagulation process for microplastics removal from stormwater

Microplastic (MP) is considered as one of the emerging pollutants in marine environments. Because of low density and small particle size (<5 mm), MPs are easily discharged into open waterways by stormwater runoff. Therefore, the aim of this study was to investigate the effect of coagulation process for the removal of different types of MPs such as low-density polyethylene (LDPE), high-density polyethylene (HDPE) and polypropylene (PP) from synthetic stormwater. The effect of different types of a coagulant such as alum and polyacrylamide (PAM), dosages of coagulants, solution pH and weathering conditions was investigated for the removal of MPs. Results found that a combination of alum and PAM performed better than standalone coagulant for MPs removal. The removal of all three types of MPs was high at low pH (3–5). It is also found that the removal efficiency of LDPE, HDPE and PP was 92 %, 84 % and 96 %, respectively under the weathering conditions. The mechanisms for MP removal were charge neutralization and hydrophobic interaction between MP and coagulant flocs. Overall, this study has confirmed that the coagulation process was very effective for removing MP particles under weathering conditions.

Towards Sustainable Museum Conservation Practices: A Study on the Surface Cleaning of Contemporary Art and Design Objects with the Use of Biodegradable Agents

Green contemporary art conservation cleaning methods are explored as sustainable museum practices, ensuring the conservator’s health and reducing the environmental impact. The performance of selected biodegradable cleaning agents, namely deionised (DI) water, a chelate based on trisodium salt of methylglycinediacetic acid (MGDA), Trilon® M, a non-ionic surfactant based on alkoxylated fatty alcohols (Plurafac® LF900), and two solvents, limonene and ethyl lactate, was evaluated for the surface cleaning of polymethyl methacrylate (PMMA), polylactic acid (PLA), polypropylene (PP), and plasticized polyvinyl chloride (pPVC). Plastic mockups were used untreated or artificially soiled, simulating particulate matter or sebum stains produced by handling. Furthermore, the efficacy of ink removal from the plastic’s surface was evaluated. Surface examination was carried out using optical microscopy (OM), scanning electron microscopy (SEM), and atomic force microscopy (AFM), while μ-Raman and gloss measurements complemented the cleaning assessment methodology. The cleaning agents’ potency depends on the type of plastic, precluding a general cleaning protocol. However, their cleaning efficacy is very promising, enriching the available choices for the cleaning of plastics, using sustainable materials and practices. This study offers valuable information to the conservation field regarding the effects of the selected biodegradable cleaning agents on each type of plastic, their application method, and their cleaning efficacy for the removal of different types of soil and ink.

Antibiotics in the municipal solid waste incineration plant leachate treatment process

ABSTRACT At present, the distribution of antibiotics in wastewater is mainly concentrated in municipal sewage treatment plants, and little attention is paid to the distribution and removal of antibiotics in landfill leachate. The concentrations of five sulfonamide, three tetracycline, and two macrolide antibiotics in leachate from a solid waste incineration plant were measured and the efficiency of the leachate treatment process in removing them was investigated. All target antibiotics were detected in the raw leachate samples. The total sulfonamide, tetracycline, and macrolide concentrations in the raw leachate ranged from 0.98 to 90.25, 1.90 to 50.64, and 146.41 to 382.90 ng/L, respectively. The leachate treatment process simultaneously removed all ten antibiotics with high removal efficiencies ranged from 96.0% to 100%. Biological and physical processes affected the removal of different types of antibiotics differently, with macrolides being more difficult for microorganisms to degrade than the other two categories. Leachate contaminants correlated to antibiotics suggesting environmental factors impact the removal of antibiotics. The accumulation of antibiotics in the leachate treatment process may create environmental problems.

Anaerobic Membrane Bioreactors for Trace Organic Contaminants with Wastewater Treatment: A Review

Trace organic contaminants (TrOCs) in water environment such as pesticides, personal care products (PPCPs), and industrial materials have the characteristics including low concentration, wide distribution range, stable chemical structure. Anaerobic membrane bioreactor (AnMBR) is a new biological treatment method. The device combines the advantages of membrane filtration technology and biological treatment process. What the performance of AnMBR for TrOCs removal should be noticed. Some research is focusing on this question, and most of research found that AnMBR has shown great promises in the application of the removal of TrOCs in wastewater treatment. This paper briefly overviews recent processes of different types of AnMBR for the removal of different types of TrOCs with the influence of kinds of factors such as temperature, salinity etc. We mainly discussed the construction of AnMBR, the classification of TrOCs, and the removal efficiency of chemical oxygen demand (COD), the removal efficiency of TrOCs, and the biogas production. For the types of AnMBRs, the removal efficiency of COD and TrOCs and biogas production are excellent. Also, the removal efficiency of TrOCs is very related to the types of the contaminants. AnMBR is not only a practical choice for TrOCs removal, but also a good choice for following sustainable development because of the good biogas production. In addition, challenges of the future research are discussed also at the end of this review to give other researchers new perspectives and ideas.

An exploratory study on the introduction and removal of different types of technical debt in deep learning frameworks

To complete tasks faster, developers often have to sacrifice the quality of the software. Such compromised practice results in the increasing burden to developers in future development. The metaphor, technical debt, describes such practice. Prior research has illustrated the negative impact of technical debt, and many researchers investigated how developers deal with a certain type of technical debt. However, few studies focused on the removal of different types of technical debt in practice. To fill this gap, we use the introduction and removal of different types of self-admitted technical debt (i.e., SATD) in 7 deep learning frameworks as an example. This is because deep learning frameworks are some of the most important software systems today due to their prevalent use in life-impacting deep learning applications. Moreover, the field of the development of different deep learning frameworks is the same, which enables us to find common behaviors on the removal of different types of technical debt across projects. By mining the file history of these frameworks, we find that design debt is introduced the most along the development process. As for the removal of technical debt, we find that requirement debt is removed the most, and design debt is removed the fastest. Most of test debt, design debt, and requirement debt are removed by the developers who introduced them. Based on the introduction and removal of different types of technical debt, we discuss the evolution of the frequencies of different types of technical debt to depict the unresolved sub-optimal trade-offs or decisions that are confronted by developers along the development process. We also discuss the removal patterns of different types of technical debt, highlight future research directions, and provide recommendations for practitioners.

Versatile nanoadsorbents based on magnetic mesostructured silica nanoparticles with tailored surface properties for organic pollutants removal

This paper addresses the development of new magnetic silica-based nanoadsorbents and evaluates their potential application in the removal of contaminants of emerging concern (CECs), polyaromatic hydrocarbons (PAHs) and aliphatic hydrocarbons. For this purpose, magnetic iron oxide nanoparticles were covered with a hybrid shell of silica and 3-(trimethoxysilyl)propyl-octadecyldimethyl-ammonium chloride (TPODAC) as structure directing agent. The as-prepared hybrid material (MMST) was further modified with trimethoxyphenylsilane, obtaining a phenyl-functionalized nanoadsorbent (MMST-Ph). Both materials were thoroughly characterized with diverse physicochemical techniques, and batch sorption tests with single-contaminant and with mixtures of contaminants were performed. MMST-Ph proved to be more efficient for the adsorption of PAHs and aliphatic hydrocarbons. The presence of TPODAC and phenyl moieties anchored on the mesostructured silica frameworks resulted to be a key factor to obtain high PAHs uptakes from aqueous media. In the case of CECs, ibuprofen (IBU), diclofenac (DCF) and carbamazepine (CBZ) were tested. These experiments demonstrated that even though MMST possesses better adsorption capacities of CECs, MMST-Ph achieved high IBU and DCF uptakes. Regeneration and reuse experiments showed that MMST-Ph can be reused in eight cycles without losing the adsorption capacity of anthracene. In the case of MMST, there was a 42% drop in the adsorption capacity of ibuprofen in the second cycle, whereas in the next seven cycles the adsorption capacity remained constant.The promising results obtained in this work strengthen the potential application of surface-modified magnetic silica nanoparticles for the removal of different types of organic pollutants from waters.

β-Cyclodextrin Polymers with Different Cross-Linkers and Ion-Exchange Resins Exhibit Variable Adsorption of Anionic, Zwitterionic, and Nonionic PFASs.

Per- and polyfluoroalkyl substances (PFASs) occur in groundwater as mixtures of anionic, cationic, zwitterionic, and nonionic species, although few remediation technologies have been evaluated to assess the removal of different types of PFASs. In this study, we evaluated the performance of three β-cyclodextrin polymers (CDPs), an anion-exchange (AE) resin, and a cation-exchange (CE) resin for the removal of anionic, zwitterionic, and nonionic PFASs from water. We found that a CDP with a negative surface charge rapidly removes all zwitterionic PFASs with log KD values ranging between 2.4 and 3.1, and the CE resin rapidly removes two zwitterionic PFASs with log KD values of 1.8 and 1.9. The CDPs with a positive surface charge rapidly remove all anionic PFASs with log KD values between 2.7 and 4.1, and the AE resin removes all anionic PFASs relatively slowly with log KD values between 2.0 and 2.3. All adsorbents exhibited variable removal of the nonionic PFASs and some adsorption inhibition at higher pH values and in the presence of groundwater matrix constituents. Our findings provide insight into how adsorbents can be combined to remediate groundwater contaminated with complex mixtures of different types of PFASs.

Application of polystyrene nanofibers filled with sawdust as separator pads for separation of oil spills

In this work we report the use of separator pads made of polystyrene nanofibers filled with sawdust for the separation of oil spills. The polystyrene nanofiber membrane was first synthetized using two electrospinning and impregnation methods, and then the synthetized pads were filled with different types of sawdust including willows, poplars and chipboards. The proposed pads were utilized for the separation of oil spills from aqueous solutions. Pre-experiments showed that the poplar sawdust with particle size in the range 40–60 mesh had the highest sorption capacity for the separation of different oil spills. The adsorption capacity of the pads synthetized by the both electrospinning and impregnation methods for the separation of the all types of oil spills decreased with increasing reaction temperature. Moreover, their sorption capacity decreased with increasing pH up to natural pH, and then slightly increased by increasing the solution pH. The results showed that under optimum conditions (reaction temperature=25°C, pH=4, and contact time=1min), the adsorption capacities of the proposed pads by impregnation method for the separation of motor oil, diesel oil, furnace oil, and crude oil were 1, 0.63, 0.97 and 0.59g/g, respectively. Moreover, the adsorption capacities of the pads prepared by electrospinning method for the mentioned oils were 1.41, 1.4, 1.5 and 1.1g/g, respectively. The synthesized pads made of polystyrene nanofibers and sawdust offered a high efficiency for the removal of different types of oil spills, and therefore they can be used as cheap, available, reusable, eco-friendly and efficient technology for the separation of oil pollution in water aqueous.

Alternative sorption filter materials effectively remove non-particulate organic pollutants from stormwater

Urban runoff contains a mixture of both particulate and non-particulate organic pollutants (OPs). Hydrophobic OPs such as higher petroleum hydrocarbons, phthalates, and polycyclic organic hydrocarbons (PAHs) are not exclusively bound to particles, but also present in runoff in colloidal and truly dissolved forms. These hydrophobic compounds can also form nano- and microsized emulsions that may carry pollutants in stormwater. Hence, it is of great importance to develop treatment technologies such as sorption filters that can remove non-particulate OPs from contaminated stormwater. A pilot plant using column bed-filters of sand as a pre-filter, in combination with granulated activated carbon, Sphagnum peat or Pinus sylvestris bark, was used to investigate the removal of non-particulate OPs from urban stormwater. Samples from the filter effluents were collected weekly; during or after rain events; and during stress tests when incoming water was spiked with contaminated sediment and petrol or diesel. All sorption filters showed efficient reduction of aliphatic diesel hydrocarbons C16–C35, benzene, and the PAHs phenanthrene, fluoranthene, and pyrene during most of the operation time, which was 18 months. During the stress test events, all sorption filters showed 100% reduction of PAH-16, petrol and diesel aliphatics C5–C35. All sorption filters released DOC and nanoparticles, which may explain some of the transportation of OPs through the filter beds. The recommendation is to use a combination of sand pre-filtration and all the studied sorption materials in stormwater filters in series, to achieve effective removal of different types of OPs. It is also important to improve the hydraulic conditions to obtain sufficient water flows through the filters.

Detection of Cyanobacterial Toxins in Water Supply Sources and Tap Water in Some Russian Cities: Searching Producers and Testing Removal Methods

For the first time, data are given on cyanobacterial toxins entering tap water, supplied to the population of some cities in Yaroslavl oblast. The detection of microcystins with their concentrations in tap water in different parts of Yaroslavl in 2013 far in excess of their safe levels in such water is due to the seasonal development dynamics of toxigenic cyanobacteria in the source of water supply, i.e., the Gorky Reservoir. The molecular-genetic analysis revealed Microcystis species as the main microcystin producers. The efficiency of some methods for removal of different types of cyanotoxins from water is estimated.

A Receding Horizon Scheduling Approach for Search & Rescue Scenarios

Many applications involving complex multi-task problems such as disaster relief, logistics and manufacturing necessitate the deployment and coordination of heterogeneous multi-agent systems due to the sheer number of tasks that must be executed simultaneously. A fundamental requirement for the successful coordination of such systems is leveraging the specialization of each agent within the team. This work presents a Receding Horizon Planning (RHP) framework aimed at scheduling tasks for heterogeneous multi-agent teams in a robust manner. In order to allow for the modular addition and removal of different types of agents to the team, the proposed framework accounts for the capabilities that each agent exhibits (e.g. quadrotors are agile and agnostic to rough terrain but are not suited to transport heavy payloads). An instantiation of the proposed RHP is developed and tested for a search and rescue scenario. Moreover, we present an abstracted search and rescue simulation environment, where a heterogeneous team of agents is deployed to simultaneously explore the environment, find and rescue trapped victims, and extinguish spreading fires as quickly as possible. We validate the effectiveness of our approach through extensive simulations comparing the presented framework with various planning horizons to a greedy task allocation scheme.

Flocculation of different types of combined contaminants of antibiotics and heavy metals by thermo-responsive flocculants with various architectures

Combined contaminants of antibiotics and heavy metals in wastewater have caused global concern. Reusable flocculant CS-g-PNNPAM with different lengths of grafted thermo-responsive branches were synthesized for the removal of different types of combined contaminants (tetracycline-Cu(II), tetracycline-Zn(II), sulfadiazine-Cu(II), and sulfadiazine-Zn(II)) from wastewater. Response surface methodology was employed to study interactive effects among wastewater temperature (X1), flocculant stock solution temperature (X2) and flocculant dosage (X3). The flocculation difficulty for different types of combined contaminants went with the sequence of sulfadiazine-Cu(II) < tetracycline-Cu(II) < tetracycline-Zn(II) < sulfadiazine-Zn(II), which was the opposite order of binding energies of antibiotic-heavy metals. This indicated combined contaminants with stronger binding interactions had the nature to be flocculated more easily. The optimal average length of grafted branches in the flocculant was obtained for each type of wastewater; Meantime, since it is not appropriate to manually adjust wastewater temperature (X1) considering energy consumption aspects, operation strategies, by adjusting stock solution temperature (X2) and flocculant dosage (X3) to reach highest removal efficiencies of antibiotics and heavy metals, were respectively optimized for several fixed X1 values, using statistical analysis of the results from jar tests. Finally, via a two-step method, antibiotics and heavy metals were sequentially recovered from flocs, and CS-g-PNNPAM was regenerated for further use, which follows the concepts of resource reutilization.

Packed Bed Photoreactor for the Removal of Water Pollutants Using Visible Light Emitting Diodes

A packed bed photoreactor was developed using a structured photocatalyst active under visible light. The packed bed reactor was irradiated by visible light-emitting diodes (LEDs) for the evaluation of photocatalytic activity in the removal of different types of water pollutants. By using a flexible LEDs strip as the external light source, it was possible to use a simple cylindrical geometry for the photoreactor, thereby enhancing the contact between the photocatalyst and the water to be treated. The visible light active structured photocatalyst was composed by N-doped TiO2 particles supported on polystyrene spheres. Photocatalytic results showed that the almost total methylene blue decolorization was achieved after 120 min of irradiation. Moreover, the developed packed bed photoreactor was effective in the removal of ceftriaxone, paracetamol, and caffeine, allowing it to reach the almost total degradation of the pollutants and a total organic carbon removal above 80% after 180 min of visible light irradiation.

Phytoremediation potential and control of Phragmites australis as a green phytomass: an overview.

Phragmites australis (common reed) is one of the most extensively distributed emergent plant species in the world. This plant has been used for phytoremediation of different types of wastewater, soil, and sediments since the 1970s. Published research confirms that P. australis is a great accumulator for different types of nutrients and heavy metals than other aquatic plants. Therefore, a comprehensive review is needed to have a better understanding of the suitability of this plant for removal of different types of nutrients and heavy metals. This review investigates the existing literature on the removal of nutrients and heavy metals from wastewater, soil, and sediment using P. australis. In addition, after phytoremediation, P. australis has the potential to be used for additional benefits such as the production of bioenergy and animal feedstock due to its specific characteristics. Determination of adaptive strategies is vital to reduce the invasive growth of P. australis in the environment and its economic effects. Future research is suggested to better understand the plant's physiology and biochemistry for increasing its pollutant removal efficiency.